Surveying Methods & Techniques Flashcards

The 'double-meridian distance' (DMD) method is primarily used to compute:

Answer: Area of a closed traverse

The DMD method is a classical computational technique used to calculate the area enclosed by a closed traverse using latitudes and departures.

The precision of a traverse is expressed as a ratio of:

Answer: Linear closure to total perimeter length

Traverse precision is stated as a ratio of the linear closure error to the total perimeter length (e.g., 1:10,000), after balancing angles but before adjusting latitudes and departures.

When using a hand level to determine elevation differences over rough terrain, the most significant source of error is:

Answer: Leveling the instrument by eye

A hand level is held and leveled by eye, introducing significant personal error in establishing a truly horizontal line of sight.

The astronomic azimuth of a line is determined by observing:

Answer: A celestial body such as the sun or Polaris

Astronomic azimuth is determined by observing celestial bodies (sun, Polaris, or other stars) and computing the direction based on time, location, and the body's ephemeris data.

In photogrammetric surveying, the 'flying height' above the datum divided by the camera focal length equals:

Answer: Photo scale denominator

Photo scale = f / H, where f is the focal length and H is the flying height above datum; thus H/f equals the scale denominator.

A surveyor must offset around an obstacle on a straight line. After placing a 90° angle and measuring 30 ft perpendicular to the line, how far must the surveyor offset back to return to the original line?

Answer: 30 ft

To return to the original line after a perpendicular offset of 30 ft, the surveyor must offset the same 30 ft back in the opposite direction at the far end of the obstacle.

In RTK GPS surveying, the 'initialization' phase establishes:

Answer: Integer ambiguity resolution of the carrier phase

RTK initialization resolves the integer number of carrier-phase wavelengths (ambiguity resolution) between satellite and receiver, enabling centimeter-level real-time positioning.